FLIGHT TESTING A PROPULSION-CONTROLLED AIRCRAFT - EMERGENCY FLIGHT CONTROL SYSTEM ON AN F-15 AIRPLANE

Aug 30, 2026

Flight tests of a propulsion-controlled aircraft (PCA) system on an F-15 were carried out at NASA Dryden Flight Research Center. The aircraft was flown with flight control surfaces locked in both manual throttles-only mode and an augmented control mode using pilot thumbwheel commands plus feedback parameters to position throttles. Results showed safe landing after major flight control failures and successful recovery from severe upset conditions, followed by descent and landing. Pilots from NASA, U.S. Air Force, U.S. Navy, and McDonnell Douglas evaluated the system favorably; manual throttles-only approaches were unsuccessful. The paper reports operation, test results, and comments.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages20

Reading Time50 min

AccessFree to download

Introduction

Description of F-15 Airplane and Instrumentation

NASA Technical Memorandum 4590 Flight Testing a Propulsion-ControlledAircraft EmergencyFlight Control Systemon an F-15 Airplane F.W.Burcham,Jr.,John Burken,and Trindel A.MaineDryden Flight Research CenterEdwards,California # FLIGHT TESTING APROPULSION-CONTROLLED AIRCRAFT EMERGENCY FLIGHT CONTROL SYSTEM ONAN F-15 AIRPLANE F.W.Burcham,Jr.John BurkenTrindel A.Maine+NASA Dryden Flight Research CenterEdwards,Califomia Abstract Flight tests of a propulsion-controlled aircraft(PCA)system on an F-15 airplane have been conducted at theNASA Dryden Flight Research Center.The airplane wasflown with all flight control surfaces locked both in themanual throttles-only mode and in an augmented systemmode.In the latter mode,pilot thumbwheel commands andaircraft feedback parameters were used to position thethrottles.Flight evaluation results showed that the PCAsystem can be used to land an airplane that has suffered amajor flight control system failure safely.The PCA systemwas used to recover the F-15 airplane from a severe upsetcondition,descend,and land.Pilots from NASA,U.S.AirForce,U.S.Navy,and McDonnell Douglas Aerospaceevaluated the PCA system and were favorably impressedwith its capability.Manual throttles-only approaches wereunsuccessful.This paper describes the PCA system opera-tion and testing.It also presents flight test results and pilotcomments. Nomenclature AGL above ground level CAScontrol augmentation system DEECdigital electronic engine control HIDEC Highly Integrated Digital Electronic Control heads-up display HUD KIASknots indicated airspeed McDonnell Douglas Aerospace,St.Louis,Missourimean sea level MDA MSL NCI navigation control indicatorpropulsion-controlled aircraftairspeed,ktsangle of attack,deg PCA V α ## Introduction After a major flight control system failure,the crew of amultiengine aircraft may use throttle manipulation foremergency fightpath control.Differential throttle controlgenerates sideslip,which through dihedral effect,results inroll.Symmetric throtle inputs may be used to controlpitch.Pilots of at least four wide-body aircraft have had touse throtles for emergency fight control.These aircraftinclude the DC-10(McDonnell Douglas Aerospace(MDA),Long Beach,Califomia),B-747(Boeing Com-pany,Seatle,Washington),and L-1011 and C-5(Lock-heed Corporation,Burbank,California). To investigate the use of engine thrust for emergencyflight control,the National Aeronautics and Space Admin-istration,Dryden Flight Research Center (NASA Dryden),Edwards,California,has been conducting flight,groundsimulator,and analytical studies.One objective is to deter-mine the degree of control power available for variousclasses of airplanes.This objective has shown a surprisingamount of control capability for most multiengine air-planes.A second objective is to provide awareness ofhrottles-only control capability and suggested manualthrottles-only control techniques for pilots.Results of sim-ulation and flight studies of several airplanes,includingthe B-720,B-727,B-747,Lear 24(Gates Learjet,Wichita,Kansas),and F-15(McDonnell Douglas Acrospace,St.Louis,Missouri),and recommended procedures for man-ual throttles-only flight have been reportcd.²Another objective is to investigate control modes that could bedeveloped for future fighter and transport airplanes.Anaugmented control system that uses pilot flightpath andbank angle inputs and sensor feedbacks to provide throttlecommands for emergency landings was developed andevaluated on a transport airplane simulation³and on anF-15 simulation.4 In 1993,a flight test program on the NASA F-15airplane investigated the performance of the PCA system,and landings using PCA control were completed.5,6 ThePCA recoveries from upset conditions,including 90°banks at 20°dives,were flown.In addition,the PCA enve-lope was expanded well beyond its original design inspeed and bank angle.During the flight test program,eightpilots flew the F-15 airplane with the

FAQs

What was the goal of the PCA emergency flight control flight tests on the F-15?

To evaluate whether a propulsion-controlled aircraft system can provide emergency flight-path and bank control using throttles after major flight control system failures, enabling safe recovery, descent, and landing.

How does the augmented PCA control mode work compared with manual throttles-only mode?

In augmented mode, pilot thumbwheel commands and aircraft feedback parameters generate throttle positioning commands. In manual throttles-only mode, the crew relies solely on throttle manipulation without the augmented feedback-based control.

What were the main findings from the pilot evaluations?

Pilots from NASA, the U.S. Air Force, the U.S. Navy, and McDonnell Douglas evaluated the PCA system favorably for its emergency capability, while manual throttles-only approaches were unsuccessful.

Aug 30, 2026

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